Susan Hart writes that the most important evolutionary function of the human attachment system is to help develop a self-regulating control system within the child. Through interactive affect regulation with the caregiver, the infant learns to self-regulate. This capacity helps the child both to be themselves and to be in touch with the other in relationship. Genes create capacities that enable change but without an environment to support these changes they will fail to take place or move in a maladaptive course.
The infant comes ready to partake in communicative transactions. However, these abilities are only acquired through practicing these interactions. The attachment between mother and child makes use of the same hormones that are involved in romantic love. Both types of attachment suppress negative emotions partly because the amygdala, the centre for fear and aggression is de-activated. The mother’s communication with the infant helps the infant to define themselves through the structure of the relationship. Through attachment interactions the infant develops relational strategies that become a prototype for handling future relationships.